// Copyright 2016 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef V8_WASM_WASM_LIMITS_H_
#define V8_WASM_WASM_LIMITS_H_

#include <cstddef>
#include <cstdint>
#include <limits>

#include "src/wasm/wasm-constants.h"

#undef max
#undef min

namespace v8 {
namespace internal {
    namespace wasm {

        constexpr size_t kSpecMaxWasmMemoryPages = 65536;

        // The following limits are imposed by V8 on WebAssembly modules.
        // The limits are agreed upon with other engines for consistency.
        constexpr size_t kV8MaxWasmTypes = 1000000;
        constexpr size_t kV8MaxWasmFunctions = 1000000;
        constexpr size_t kV8MaxWasmImports = 100000;
        constexpr size_t kV8MaxWasmExports = 100000;
        constexpr size_t kV8MaxWasmGlobals = 1000000;
        constexpr size_t kV8MaxWasmExceptions = 1000000;
        constexpr size_t kV8MaxWasmExceptionTypes = 1000000;
        constexpr size_t kV8MaxWasmDataSegments = 100000;
        // Don't use this limit directly, but use the value of {max_mem_pages()}.
        constexpr size_t kV8MaxWasmMemoryPages = 32767; // = ~ 2 GiB
        constexpr size_t kV8MaxWasmStringSize = 100000;
        constexpr size_t kV8MaxWasmModuleSize = 1024 * 1024 * 1024; // = 1 GiB
        constexpr size_t kV8MaxWasmFunctionSize = 7654321;
        constexpr size_t kV8MaxWasmFunctionLocals = 50000;
        constexpr size_t kV8MaxWasmFunctionParams = 1000;
        constexpr size_t kV8MaxWasmFunctionMultiReturns = 1000;
        constexpr size_t kV8MaxWasmFunctionReturns = 1;
        // Don't use this limit directly, but use the value of FLAG_wasm_max_table_size.
        constexpr size_t kV8MaxWasmTableSize = 10000000;
        constexpr size_t kV8MaxWasmTableInitEntries = 10000000;
        constexpr size_t kV8MaxWasmTables = 1;
        constexpr size_t kV8MaxWasmMemories = 1;

        static_assert(kV8MaxWasmMemoryPages <= kSpecMaxWasmMemoryPages,
            "v8 should not be more permissive than the spec");
        static_assert(kV8MaxWasmTableSize <= 4294967295, // 2^32 - 1
            "v8 should not exceed WebAssembly's non-web embedding limits");
        static_assert(kV8MaxWasmTableInitEntries <= kV8MaxWasmTableSize,
            "JS-API should not exceed v8's limit");

        constexpr uint64_t kWasmMaxHeapOffset = static_cast<uint64_t>(
                                                    std::numeric_limits<uint32_t>::max()) // maximum base value
            + std::numeric_limits<uint32_t>::max(); // maximum index value

        // Defined in wasm-engine.cc.
        // TODO(wasm): Make this size_t for wasm64. Currently the --wasm-max-mem-pages
        // flag is only uint32_t.
        uint32_t max_mem_pages();
        uint32_t max_table_init_entries();

        inline uint64_t max_mem_bytes()
        {
            return uint64_t { max_mem_pages() } * kWasmPageSize;
        }

    } // namespace wasm
} // namespace internal
} // namespace v8

#endif // V8_WASM_WASM_LIMITS_H_
